There is a home test for infidelity. I have not used it and do not know if it works. I am mentioning it to let you know that such a resource exists. This is not an endorsement, but merely passing on the existence of such a product. It is called Check-Mate. It is available through the site and also through Amazon.com . It allows you to check for activity by testing the clothing of your spouse.
Best Regards,
Jeff Murrah